Thanks for sharing, @till.
I haven't heard of #wire.
Also, in Switzerland, there is a second app that seems to be good and en vogue there (if I remember the name, I'll try to repost it here).
Two key issues:
1) acceptance/network effect. If you cannot get your network to move, too. No use.
2) Counterparty risk: if it is a private corp, it will be snatched up...